Doors and Windows - What's the Story?

Discussion in 'Boatbuilding' started by CatBuilder, Apr 2, 2012.

  1. CatBuilder

    CatBuilder Previous Member

    I may do a high speed resin infusion on them using normal, 2 hour cure epoxy. The window supports are fairly small pieces, area wise.

  2. david@boatsmith
    Joined: Aug 2008
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    Location: Jupiter Fl USA

    david@boatsmith Senior Member

    Your glass will probably be 1/4" thick. When you are laying up the panels the windows go in you will have to mold in a flange to land the window on. This flange will be sized to allow about 3/8" of adhesive thicness between the fiberglass and the window glass. Plus your window thickness will give you a 5/8" deep rebate.You also need a minimumof 3/8" of adhesive around the perimeter of the window.The bonding surface on these size windows is typicaly about 1 1/2" wide. It is imperitive that there is an adequte thickness of adhesive or it will tear with expansion and contraction and fail. We use Sikaflex 296 for mineral glass for the inintial bonding and then pack the rest of the void with 295 uv. Sikaflex will engineer all of this for you if you ask. Sikaflex as well as some other adhesive manufaturers wants to see a frit intsalled to the mineral glass to protect the adhesive from UV. A frit is a baked on black ceramic coating that prevents the uv from passing through the glass and degrading the adhesive. You can easily see this on the perimeter of the windsheild of your car. Not all boatbuilders do this. It is expensive and comes with some leadtime.
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  3. hoytedow
    Joined: Sep 2009
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    Location: Quam prospectum!

    hoytedow Fly on the Wall - Miss ddt yet?

    Good thinking.
  4. CatBuilder

    CatBuilder Previous Member

    David, thank you. That is a gold mine of information to keep in mind as I get closer to this.

    The window thickness is in the plans... I'll have to take a look at that and add up the rebate to do with your info.

    That's some great information. Just have to wrap my head around it all.
  5. Corley
    Joined: Oct 2009
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    Location: Melbourne, Australia

    Corley epoxy coated

    Attached Files:

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  6. CatBuilder

    CatBuilder Previous Member

    Thanks, Corley. I have that image in my plans but it doesn't take you the one step further to know how to make the panel the window rests on.

    Ah! Just looked at that image. Mine doesn't say "carry glass", so i guess that's why I didn't know.
  7. Whimsical
    Joined: Aug 2010
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    Location: Australia

    Whimsical Junior Member

    are all your windows flat panels?
    If they are u can mould the frame on a tabel as people have suggested but if they have much curve it becomes problematic. I used this metod to make frames for the potrtholes to make a flat surface on heavily curved side decks.
    The common way here on custom builds is to lay up a thin flat frame,maybe 900 grms to the shape of the hole inside dimensions to allow for the support flange outside dimension to allow about 30mm on the cabin side. Glue this to the inside and then apply 3kg of glass in ever increasing sizes to make the frame strong and spread the load, at least 300 mm away from the edge. on the outside radius and at least 900 grams of glass to connect to the outer skin.
    I actually did it with 9mm ply to fully line the inside so i get a flat interior with no bulge around the windows.
    Before doing this cut the hole and decore deep and insert uni to reinforce.
    I have added some 5 inch carbon half pipe about 5mm thick to reinforce the uprights between the windows. Seen so many windows that i could easily kick out. Whatever u do make it bloody strong and not the flimsy things seen on so many boats.

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  8. rxcomposite
    Joined: Jan 2005
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    Location: Philippines

    rxcomposite Senior Member

    I was going to respond but was quite busy. Time flies quickly.

    Whenever you cut an opening into the structure, you need to reinforce the edges. At this point, you probably did not, so you need to reinforce the opening with a frame. Not to worry as most of the glass are either mirror images of each other or identical in size so you need only to make a few molds,

    The same with the doors. you have to make door jambs and install it in place.

    My last project had about 36 flush windows per boat X 6 boats, so 200+ glass was installed the Sikaflex way. It works.

    I will post later the sketches. One question though, how much variation do you have in the cored lamination thickness? Plus/minus 1/16"?
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  9. CatBuilder

    CatBuilder Previous Member

    Thanks, guys. To answer rx's question, the window panels are all within 1/16. The aft wall of the deckhouse is all the same thickness, but different from the other deckhouse windows, and just about all the doors on the interior bulkheads are different.
  10. rxcomposite
    Joined: Jan 2005
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    rxcomposite Senior Member

    CatB here is the sketch.

    If you have about 1/16" tolerance on the laminate you won't have much of a problem. Note that the frame is two piece and must be set from the outside and the inside.

    For the window frame, you can rely on the mold releif angle to release it from the mold. For the doors where clearance is critical for good looks, you can make it 90 degree. To release it, you need to cut one side to break it open.

    When fabricating the parts, vacuum bag it to have as little resin as possible and keep variation in thickness to minimum. The part needs to be strong. Remember, pressure comes from outside. The doors must open from outside, not inside. If you want it opening from the inside, you must have a storm door that opens from the outside.

    Follow the recommended sealant thickness and backfill.

    Composite door is a tricky part. If you haven't experienced doing one, I will provide a sketch.

    Attached Files:

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  11. CatBuilder

    CatBuilder Previous Member

    That was one incredible post, Rx. Thank you so very much for taking the time to draw that out in color!

    It makes it so much more understandable.

    My major lack of understanding was with the windows. I didn't understand how you could bring the 3mm of glass around, but now I do. Using the bog in there would make sense.

    All exterior type doors will be proper (opening out) with a rubber strip to help in case of waves boarding.

    Composite doors? No, I do not have information on that. Is there a trick? There must be if you are talking about drawing it. I hadn't though that far in advance yet and figured you just cut out your shape, glass it and you're done! ha ha ha

    Pretty naive, I'm thinking. :)
  12. rxcomposite
    Joined: Jan 2005
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    Location: Philippines

    rxcomposite Senior Member

    No problem. I was drawing it in between boring commercials while watching TV.:cool:

    Perhaps you did not get the window setting correctly. You hot glue or double side tape the dowel/bar and spacer to the glass so that it acts as a "hanger" and the glass does not sink into the lip where the sealant goes. For inclined or vertical installation, place a wedge at the bottom so the glass does not slide down. Use hot glue to temporarily fix the dowel to the frame. You can knock it off afterwards when the sealant cures.

    The simplest door and door jamb would be square edged. You can also make a mold for that. The key part is the series of hard points embedded to take care of local loads like hinges, doorlocks, and striker plate.

    More complex doors have radiused corners, soft edges, and window glass. You can make a professional looking door using melamine board as a base and wood as a perimeter base. If your carpentry skill is good enough, you need only to make one (half) mold for every door size and modify the same half mold for the other side. Skill means if you make one half part and mate the other half, it will not come up skewed. The tricky part is the knock away inserts.

    You need a router and some modeling clay to round off the edges.I will work on the drawing.

  13. groper
    Joined: Jun 2011
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    Location: australia

    groper Senior Member

    i have another way cat, i used this method for doing the edges on wakeboards/kiteboards i used to make years ago...

    assuming your starting with a virgin peice of foam like corecell etc...

    mark out the edge of the landing your windows will be bonded to, make the recess the desired depth and also cut out the edge of landing completely with the router instead of a jig saw etc because you will use the gap made by the router blade to fill with structural bog or woven rovings, folded up uni-directional glass etc... lay it in there on a flat non stick table... you can leave the waste peice of foam from the window cutout in place for now as it will hold everything in place whilst you build the solid edge...

    Now you good to go with the cabin panel lamination over this, preferably under vacuum bag or via infusion. the glass will go down tight into the recess from the vacuum bag and over the solid landing edges you already created... it will automatically leave a resin cove a little from the slight bridging of the vac bag... once its cured, simply knock out the foam waste peice inside the cutout and sand off the daggy bits of foam to the solid edge you made first...

    make sense?
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